L The bark of these spp. is chewed as a remedy for coughs (Lane Pool, in Dalziel, 1937) and has been used for the treatment of stomach pains and syphilis (Staner and Boutique, 1937).

C Some forty alkaloids have been identified in Uncaria spp. They are mainly of the hetero-yohimbine and corresponding oxindole types although pyridino-indoloquinolizidines (e.g. angustine) and harmane are also present. Rhynchophyl-line, rotundifoline and isorhynchophylline, etc. have been reported as well as gambirine and roxburghines (the latter in extremely limited quantities) as could be expected in view of the close relation with the genus Mitragyna (Merlini et al., 1972; Phillipsonera/., 1973; Phillipson and Hemingway, 1973,1975).

P Antispasmodic and sedative action is attributed to the 'hooked thorns' of the plant (Kariyone, 1971). The related U. rhynchophylla (not found in West Africa) is, according to the dose administered, reported to have either muscle-relaxant or muscle-stimulant activity (Harada and Ozaki, 1978,1979).

Alchornea cordifolia (Schum. & Thonn.) Müll. Arg. syn. (Schousboea cordifolia Schum. & Thonn., A. cordata Benth.) EUPHORBIACEAE

Alchornea floribunda Müll. Arg.

L The root of A. floribunda, called niando in the Congo region (Zaire) is used by the Africans as a stimulating intoxicant and aphrodisiac. After reducing it to a powder, it is either mixed with food or macerated for several days in palm wine and consumed to provide energy for tribal festivities or warfare. It is said to provide a state of intense excitement followed by a deep, sometimes fatal, depression. It is further considered an excellent remedy for urinary, respiratory and intestinal disorders (Dalziel, 1937; Oliver, 1960).

C According to their origin (Ivory Coast, Guinea) and the time of conservation, the root and bark of A. cordifolia have been found to contain 0.03-0.26% of total alkaloids: the highest amounts were found in the most recent samples (Bennet, 1950). Thin-layer chromatography revealed two principal alkaloids, closely related to but not identical with yohimbine (Paris and Goutarel, 1958). Ferreira et al. (1963b) found in the roots of the plant in Portuguese Guinea 0.07% of alkaloids together with gentisic and anthranilic acids and suggest that gentisic acid could be a possible precursor in the biosynthesis of yohimbine. In addition, in the leaves and bark of this species, 10% and 11% of tannins, respectively, have been found (Bennet, 1950).

P The extract of the roots of A. fbribunda has sympatholytic activity (Raymond -Hamet, 1933). It considerably increases the sensitivity of the nervous system towards adrenaline. In the dog, doses of 0.5 g/kg produce a slight hypotension, followed by a slight hypertension. Higher doses produce a gradual decrease of the carotid pressure, which returns only very slowly to its original value (Raymond-Hamet, 1954). A patent has been obtained for the use of the leaf alkaloid as a spasmolytic (Goutarel R. Brevet français 2087982 of 5.5.1970). Guedel (1955) obtained positive results in clinical experiments with root and leafy stem extracts in the treatment of icterus in Abidjan.

Grewia bicolor Juss. syn. (G. salvifolia Heyne ex Roth.) TILIACEAE

Grewia carpinifolia Juss. syn. (Vinticena carpinifolia (Juss.) Burret) Grewia lasiodiscus K. Schum. syn. (G. kerstingii Burret, Vinticena lasiodiscus (Schum.) Burret, V. kerstingii (Burret) Burret)

L The Grewias have edible fruits (sometimes made into a fermented drink). The shoots of G. carpinifolia are given to sheep at lambing to help delivery (Irvine, 1930) and women put the roots in soup when approaching childbirth (Dalziel, 1937).

C The roots of all three species contain mucilage and catechuic tannins. In G. carpinifolia gallic tannins are also reported. The barks of all spp. were found to contain amines (aspartic acid and probably proline) but no alkaloids, quinones, saponosides or histamine-like substances were reported. The flowers, like those of other Tiliaceae, contain farnesol (Paris and Théallet, 1961).

P The bark extract of the Grewia spp. has a more or less distinct depressive action on the guinea pig ileum. This is contradictory to the effect observed on rat or rabbit duodenum (Paris and Théallet, 1961). The action appears to be directly muscular, and the authors suppose that the active principle belongs to the aminophenols. Binet et al. (1972) observed that farnesol has spasmolytic action on the smooth muscle fibres of the intestine as well as on those of the Oddi sphincter, while oxytocic action has been reported in a non-West African species, G. elyseoi (Paris, 1956). Further, farnesol has been found to have psychosedative action in cases of psychic over-excitement; in higher doses it influences psychomotor defence reactions. Farnesol has proved to be antagonistic to the excitant effect of caffeine and to potentiate the hypnotic effect of barbiturates without being hypnotic itself (Paris, 1956).

Pentaclethra macrophylla Benth. MIMOSACEAE

Oil bean tree, Congo acacia

L A decoction of the bark is used in Nigeria in a lotion for healing sores. In Sierra Leone, the bark has been reported to be an anthelmintic. The Ibos hold a baby suffering from adekuku (epileptic fits) in the smoke of the burning leaves (Irvine, 1961).

C The beans yield 30-36% of a non-drying oil, the seed kernels 44—45%. This oil is suitable for soap and candles and for lubrication (Oliver, 1958). In the shell of the nut the presence of the alkaloid paucine, as well as a fixed oil and resinous constituents, have been reported (Henry, 1949, p. 776). In the Ivory Coast, the nut has been found to contain 55.4% lipids, 28.5% of protides and 12.2% of glucides. The oil contains mainly glycerides of linoleic, oleic and lignoceric acids (Busson, 1965).

P Correia da Silva and co-workers reported that 0.5-1 ml of a 1:10 aqueous decoction of the bark causes violent and long-lasting contractions of the isolated guinea pig uterus (Correia da Silva et al., 1960). Later they found that the same extract decreases smooth muscle tone in the guinea pig trachea and in rat, rabbit and pig blood vessels and that it antagonizes the effect of acetylcholine and histamine on the intestine of the guinea pig (Correia da Silva and Quiteria Paiva, 1970). The anticholinergic effect was confirmed by Sandberg and Cronlund (1982).

Newbouldia laevis (Beauv.) Seem, ex Bureau syn. (Spathodea laevis Beauv.) (Fig. 3.8) BIGNONIACEAE

L In Ghan^ in 1891 Easmon found N. laevis bark effective in the treatment of malaria and dysentery and attributed the action to a tonic effect on involuntary muscles and mucous membranes. In Lagos, an infusion of the bark and rootbark is used against convulsions in children and the flowers and leaves are used in a liniment for skin

Fig. 3.8. Newbouldia laevis (Beauv.) Seem, ex Bureau.

Fig. 3.8. Newbouldia laevis (Beauv.) Seem, ex Bureau.

diseases. The juice of the fresh leaves is applied to wounds (Dalziel, 1937; Watt and Breyer-Brandwijk, 1962). C From the roots of trees growing in Portugese Guinea, four different alkaloids have been isolated. One of the bases was identified as harmane (Ferreira et al., 1963a). Alkaloids have also been found in the bark but not the leaves of Congolese specimens. In the leaves and bark, no flavonoids, saponins, quinones, terpenes or steroids could be detected (Bouquet, 1972). P The alkaloids obtained from the specimens from Guinea show an inhibiting action upon the isolated rabbit duodenum and guinea pig ileum. They antagonize the action of acetylcholine and histamine on the guinea pig ileum but do not act on the isolated uterus (Correia da Silva et al., 1966).

Lantana camara L. syn. (L. antidotalis Thonn.) VERBENACEAE

Wild Sage, Bahama tea L In Nigeria and Senegal, an infusion of the leaves is used as a treatment against coughs and colds. In Senegal, it is also given to asthma patients as it is said to relieve dyspnoea and suffocation. A mixed infusion with Ocimum is considered to have diaphoretic and antipyretic action. C The leaves, stems and flowers were found to contain the triterpenes a-amyrine, /3-sitosterol, lantaden B and a triterpenoid acid. In addition, a lactone was obtained from the hydro-alcoholic extract. The triterpenoid acid, later named lantaden A, has been identified as rehmannic acid (Louw, 1948,1949). The essential oil found in the leaves is rich in caryophyllene, eugenol, a-phellandrene, dipentene, terpineol, geraniol, linalol, cineol, citral, furfural and phellandrone (Ahmed et al., 1972). Sugars and lipids have also been reported to be present. P The plant, if ingested, causes photosensitization in sheep (Seawright, 1963; Sea-wright and Allen, 1972). In an extensive bibliographical research, Watt and Breyer-Brandwijk (1962) showed that the icterogenous action of the plant is the basis of the intoxication. Intoxications in children accidentally eating the berries showed an icterogenous effect (Wolfson and Solomons, 1964) and rehmannic acid has been shown to be an icterogenous triterpenoid acting on the permeability of the liver cells, mainly by blocking the excretion of bile pigments (especially bilirubin and phyllo-erythrine), thus causing icterus and abnormal sensitization (Heckel et al., 1960; Dhillon and Paul, 1971; Dwivedieia/., 1971; Seawright and Allen, 1972). Lantanin, later identified as the isomeric triterpenes lantaden A and B, was mentioned in The US National Dispensary, 1926, as an antispasmodic, but has proved to be too toxic. Some of the constituents of the essential oil account for the antiseptic effect.

(c) Stimulants of the cholinergic and adrenergic systems

Cissus quadrangularis L. syn. (Vitis quadrangularis (L.) Wall, ex Wight & Am.) (Fig. 3.9) VITACEAE

Edible stemmed vine, Vigne de Bakel (Senegal) L The fresh leaves and pounded stems are applied to burns, wounds and also to saddle sores of horses, camels, etc. The stem is also used for gastrointestinal complaints or as a stomachic sometimes taken in the form of the succulent stem boiled and sugared. In Guinea the stems and leaves are given to cattle to induce milk and in Senegal a decoction of the stems and leaves is used as a friction and wash in pains with fever and in malaria (Dalziel, 1937).

C The plant was found to contain a steroid which can be separated into two fractions (Sen, 1966). Further, a water-soluble glycoside has been obtained from the plant, which on oral administration had no toxic effect in mice, rats or guinea pigs (2 mg/kg for 10 days). On intravenous administration, however, the animals showed convulsions and died with 5 min.

P Das and Sanyal (1964) noticed that an alcoholic extract of the plant (containing resins and sterols) acted upon the isolated intestine and the uterus of rabbits and albino rats in a manner comparable to that of acetylcholine. The effect was also observed in situ on the tracheal and intestinal muscles of the dog. The LD50 was 15.5 mg/kg in guinea pigs. The extract has a favourable effect on gastrointestinal evacuation and is recommended in cases of indigestion, dyspepsia and gastritis (Das and Sanyal, 1964). In dogs the glycoside fraction produced dose-dependent hypotension. The negative chronotropic effects on the myocardium can be overcome by 7.5 M calcium (Subbu, 1970). It is believed to act on the cell membrane by inhibiting the movement of Ca2+ into the cell substance (Subbu, 1971). Intramuscular administration of an extract of C. quadrangularis to rats and local use as an ointment in dogs was shown to reduce the convalescence time of experimental cortisone-treated fractures by 33% (cortisone has an anti-anabolic action and delays consolidation) (Udupa and Prasad,

Fig. 3.9. Cissus quadrangularis L.

Fig. 3.9. Cissus quadrangularis L.

1964; Prasad and Udupa, 1963). A potent anabolic steroid isolated from the plant has been shown to have a marked influence on the rate of fracture healing; it induces an early regeneration process of all connective tissues involved in the healing and a quicker mineralization of the callus (Udupa et al., 1965). Indeed, after 6 weeks the bones recovered 90% of their original strength. Calcium-45 uptake studies indicated early completion of recalcification and earlier remodelling. This steroid fraction appears to have androgenic properties and produces an increase in body weight and the total weight of the testes in animals (Prasad and Udupa, 1963; Udupa and Singh, 1964; Udupa et al., 1965; Prasad et al., 1970).

The pathway to the site of action of the phytogenic steroid can be studied by tagging it with radioactive 14C. The site of action is located in the rat by microautoradiography. The probable pathway seems to be through the anterior pituitary gland, then by the adrenals and testes. After some metabolism in the liver, the steroid reaches the osteogenic cells at the fracture site, where it seems to exert a stimulating effect on the healing of the fracture (Prasad and Udupa, 1972).

Sida cordifolia L. MALVACEAE

L The plant provides fibre and is a troublesome weed. In India the rootbark, pulverized and mixed with oil of sesame and milk, has been said to be effective in cases of facial paralysis and sciatica (Chopra etal., 1956). Ephedrine has been found in this plant and has been listed in the Indian Pharmaceutical Codex (1953) for the relief of hay fever and asthma (Oliver, 1960).

C Recent analyses have revealed that ephedrine and ^-ephedrine constitute the major alkaloids in the aerial parts (minor bases in the roots). From the aerial parts and the roots the following were also obtained: /3-phenylethylamine, carboxylated trypt-amines, quinazoline alkaloids, S(9)Nb-tryptophan methylester, hypaphorine, vas-icinone, vasicine and vasicinol in varying amounts (Ghosal et al., 1975). In S. acuta and S. rfaombifolia, also found in West Africa, the main alkaloid in Sri Lanka proved to be cryptolepine, which was first found in Cryptolepis (Gunatilaka et al., 1980). In 5. acuta growing in India, the alkaloids cryptolepine and ephedrine were found in the roots as well as a-amyrin (Krishna Rao et al., 1984).

P The favourable combination of three sympathomimetic amines and a potent bronchodilator principle (vasicinone) would, according to Ghosal et al. (1975), account for the major therapeutic uses in asthma, hay fever, etc. Vasicine is said to be a promising uterotonic abortifacient (it is mainly obtained from Adhatoda vasica (Gupta etal., 1978).

Anticonvulsant and antipyretic activities of the plant (collected in India) have been observed by Dhar et al. (1968). In addition these authors note extensive antibacterial, antifungal and antiviral effects as well as antiprotozoal action on Entamoeba histolytica and anthelmintic action towards Hymenolepis nana and Ascarides galli. A hypoglycaemic effect and action on the smooth muscles and heart were also reported. Anticancer activity against human nasopharynx carcinoma (in tissue culture) and lymphoid leukaemia and sarcoma 180 in mice were revealed in CCNSC tests in the USA (Dhar et al., 1968).

Crateva religiosa Forst. syn. (C. adansonii Oliv.) CAPPARIDACEAE

L The root is used in Nigeria as a febrifuge and the Yorubas apply the leaf as a mild counter-irritant for headache (Dalziel, 1937). In India, the stembark has been used as an antipyretic, stomachic, laxative and diuretic (Chopra et al., 1956). In the Philippines, the juice of the bark is used to treat convulsions (Quisumbing, 1951).

C In India, the bark was found to contain a gum, a saponoside and tannins. From the air-dried powdered bark, the triterpenes lupeol, /^-sitosterol and lupeol acetate have been isolated. The water-soluble portion contained traces of quaternary and tertiary bases and sugars. The tertiary bases were found to contain both sulphur and nitrogen (Bhandari and Bose, 1954; Chakravarti et al., 1959; Kjaer and Thomsen, 1963; Smolenski et al., 1972; Kondagbo and Delaveau, 1974). In the leaves and twigs nine flavonoids, mainly rutin, quercetin and isoquercetin have been reported (Hegnauer, Vol. 3, p. 362).

P The water-soluble fraction of the air-dried bark had spasmodic action, which was not blocked by atropine, on the uterus of the rat, guinea pig, rabbit, dog and humans. It was also observed to have cholinergic action on the isolated ileum of the guinea pig and on dog tracheal muscle preparations. Nicotinic action of the extract on the ganglia has also been noted by Deshpande (1973). Clinically, ingestion of a powder of the whole plant has been observed to improve the tone of the urinary bladder in 12 cases of post-operative prostatic enlargement and it could even remove smaller stones from the ureter and bladder and control various urinary tract infections. This action has been attributed to the cholinergic action of the drug on smooth muscles (Deshpande, 1973).

A petroleum ether extract and sterols isolated from the stembark significantly inhibited the acute inflammation induced by carrageenan and histamine in albino rats and inhibited the early and delayed phases of inflammatory changes in formaldehyde-induced arthritis (Ramjelal et al., 1972). Total extracts had an inhibiting effect towards Shigella dysenterica and the leaves and stembark had (considerable) anticancer action on sarcoma 180 (Kerharo and Adam, 1974) and on lung cancer (leaves) (Abbot et al., 1966).

Borreria verticillata (L.) Mey. syn. (Spermacoce verticillata L., 5. globosa Schum. & Thonn.) RUBIACEAE

L A lotion of the plants is used in Senegambie for febrile children and in the treatment of leprosy, furuncles and paralysis (together with Datura metel). It is also said to be diuretic and abortive (Dalziel, 1937; Kerharo, 1968).

C Plants collected in the Ivory Coast and Senegal have been found to contain 0.20% of total alkaloids. Emetine or cephaline, reported in older publications (Moreira, 1963) could not be detected, but two other alkaloids have been reported to be present in the aerial parts. They are borreverine, with a tetrahydro-/3-carboline nucleus, and borrerine (Pousset et al., 1973). An essential oil is found in the aerial parts; from it, a sesquiterpenic lactone was isolated (Benjamin, 1979). Iridoids, daphyloside, asperuloside and feutoside have been obtained from the rootbark (Sanity et al., 1981).

P Pharmacological screening in Brazil showed that this plant has a stimulating action on the uterus of the rat and on the duodenum of the rabbit. No actions on the blood pressure and respiration of the cat could be detected nor were any effects observed on the striated frog muscle and guinea pig intestine. Toxicity to mice and fish was nil (Barros et al., 1970) and no insecticidal activity was found (Heal and Rogers, 1950). The antimicrobial activity of the essential oil was tested by Benjamin (1979) and revealed inhibition of Escherichia coli and Staphylococcus aureus.

Cardiospermum halicacabum L. syn. (C. microcarpum Kunth) SAPINDACEAE L In Nigeria the leaves are sometimes rubbed on the skin for the treatment of skin eruptions, itch, etc. or applied as a poultice to swellings. The juice of the stem is dropped in the eye to treat ophthalmia. The leaf and root are used as a remedy for nervous diseases in many countries (e.g. Australia and South Africa) (Watt, 1967). After eating the seeds in quantity children may develop epileptiform convulsions. C Stigmasterol, probably in the form of a glycoside, and quebrachitol have been isolated from the air-dried plant in India and proanthocyanidin and apigenin have been isolated from an alcoholic extract of the roots (Dass, 1966). P The water-soluble fraction of a dried alcoholic extract of the seeds produced an initial depression followed by marked stimulation in the isolated frog heart preparation (Moti and Deshmanhar, 1972).

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